Lumapower LM-301 is a good Cree Host (Pictures missing, new ones on page 2)

[EngrPaul]

paxxus,

The stock reflector measures .482" (12.24 mm)
The mod I did measures .469" (11.91 mm)

I didn't remove as much as I originally though

 

[EngrPaul]

paxxus,

I did a height boost to an emitter star board, when upgrading my BLIMP here:

https://www.candlepowerforums.com/threads/148417

 

[paxxus]

Thanks! So you took off only 0.3mm, not much - I guess I'll have to sand down one of those copper discs in order to make it thinner like you did that coin in your other thread. Anyway, I'll decide which way to do this mod when I have all the parts in my hands.

 

[EngrPaul]

paxxus,

I didn't like how green the WH emitter was, so I replaced the emitter with a WC/X0. The color is almost exactly like the stock Luxeon.

I also filed off some more reflector to tighten the beam. It focused sharper without creating any more rings.

The result is surprisingly as good as stock, just brighter, and a fantastic spill.

 

[paxxus]

OK, cool. I'm really looking forward to doing this, it'll be great fun. But it won't before at least a week. I have no idea what color bin the P4s I ordered from Cutter are though. I'm leaning towards soldering a copper plate to the CreePCB and then sanding it down to the proper thickness, should be a lot easier than your coin-mod due to the softness of the copper. The copper plates from SS are about 1mm thick, so it looks like I should take perhaps 0.5mm off (1mm minus 0.3mm minus whatever more you sanded off to tighten the beam (I estimated 0.2mm)). The problem with doing it this way, is that there is no way to make adjustments once the Cree is soldered onto the copper plate. That's why I really appreciate your measurements.

 

[EngrPaul]

The LM301 is also a very good host for the Seoul P4. No reflector mod is necessary.

Seoul (Left), Cree (Right) in all pictures. Last picture is the same beamshot, underexposed 2 stops.

 

[Pumaman]

good job. looks like throw vs. flood on the seoul vs cree. I'll likely try both as well

 

[EngrPaul]

BTW, the Seoul is 6500K, and the Cree is WC.

I don't know what the deal is with the LM-301. The WH tint was too green for me, so I swapped the emitter for the WC shown. It's still quite warm!

 

[Pumaman]

seems the lower the drive level, the warmer it is, but I'm not certain thats all of it.

 

[paxxus]

I started out with the Seoul mod firstly since that seemed easier to do. And it was real easy. I drilled out all the vias in a Shoppe Cree PCB (rev 1) in order to break the electrical connection, and I then cut it into a little disk which I then dropped into the pit where the old lux sat. This will then isolate the positive case of the Seoul from the negative pill; everything was gunked up in thermal goo. Then I dropped in the Seoul and soldered it. Done! No sanding or anything. The throw is very good with a tight hot-spot and very nice beam overall.

I don't really like the tint of the Seoul P4 U-bin that much though, but it's still a very nice upgrade. Mine looks exactly like EngrPaul's pic.

Next up will be the Cree mod, I got P4 WG bins, not exactly WC but hopefully it's close enough. I'm really looking for a nice flood so I'm looking forward to see the results.

 

[paxxus]

Did the Cree mod too (WG-P4 bin). I ended up balancing two of the small SS copper discs below the SS CreePCB. No dremeling or sanding of the pill or reflector was then needed. If it sounds tricky to do, it was! But the result is very nice. My beam shots look like the ones shown by EngrPaul.

If I understand things correctly a Seoul P4 U-bin should be brighter than a Cree P4, but to my eyes the Cree is slightly brighter. The Seoul has better throw but the tint absolutely stinks. The Cree mod has IMO perfect balance between throw and spill.

I'm not going to bother with those Seouls again, unless I know the color bin.

 

[EngrPaul]

I've used both of these LM-301 mods (Seoul and Cree) from time to time over the last week or so. The LM-301 with Seoul is always the more useful beam.

 

[paxxus]

Hmm, I think I got a real lottery loser Seoul both in terms of output and tint, my Cree is definitely brighter (and white). I ordered some new Seouls from PhotonFanatic with known bin, looking forward to replacing the Seoul with a better one.

One thing I've noticed: My Cree modded LM301 kind of flickers a little, especially as it heats up (running on 1xAA Alkaline). The Seoul LM301 doesn't do this. Anyone noticed this, or do I just have a bad driver in my light...?

 

[EngrPaul]

One thing I've noticed: My Cree modded LM301 kind of flickers a little, especially as it heats up (running on 1xAA Alkaline). The Seoul LM301 doesn't do this. Anyone noticed this, or do I just have a bad driver in my light...?

Make sure the reflector isn't pushing on the emitter. Try backing off the pill a quarter turn and see if it goes away.

 

[paxxus]

Make sure the reflector isn't pushing on the emitter. Try backing off the pill a quarter turn and see if it goes away.

You solved my problem! I didn't realize how far I had actually pushed the Cree into the reflector, those two copper discs lift it almost as much as possible. When the light heated up the top terminals on the Cree must have made intermittent contact to the reflector due to the expansion from the heat. I didn't back out the pill, instead I isolated the top terminals with some thin tape. I'm not sure the tape will stand the heat long term, so I'm going to get some of that Kapton tape.

:thanks:

PS.: I like the Cree beam best, wonderful flood with quite decent throw, YMMV.